Function pointer and Call back functions

callback is a reference to executable code, or a piece of executable code, that is passed as an argument to other code.

The complete program has three files: callback.c,  reg_callback.h and reg_callback.c

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/* reg_callback.h */

typedef void (*callback)(void);

void register_callback(callback ptr_reg_callback);

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/* reg_callback.c */

#include"reg_callback.h"

 

/* registration goes here */

void register_callback(callback pCallback)

{

    printf("inside register_callback\n");

    /* calling our callback function my_callback */

    (*pCallback)();                                  

}

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/* callback.c */

#include"reg_callback.h"

/* callback function definition goes here */

void my_callback(void)

{

    printf("inside my_callback\n");

}

 

int main(void)

{

    /* initialize function pointer */

    callback  pCallback=my_callback;                           

    printf("This is a program demonstrating function callback\n");

 

    /* register our callback function */

    register_callback(pCallback);                             

    printf("back inside main program\n");

    return 0;

}

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